The invention relates to a power generator unit composed of a generator and a piston internal combustion engine as the drive, particularly composed of a synchronous generator and a diesel engine, pursuant to the preamble of claim 1.
Such a power generator unit, combined with a pump unit, is described in DE 19721527.
Usually, power generator units with permanent magnet excitation lack a simple form of regulation to adapt the generator voltage to various load states. In other power generator units, a possibility for regulation technology intervention is provided on the exciter side of the generator, either in the form of slip rings that tend to wear, or by installation of a rotating rectifier with an exciter machine.
In contrast, the present invention is based on the task of avoiding complicated measures of regulation technology. In particular, it is intended to guarantee that predetermined voltage tolerances are adhered to during load changes, in favor of a continuous voltage progression that is essentially independent of the phase position.
This task is accomplished according to a proposal of the invention, in accordance with the characteristic of claim 1.
Because the stator of the generator is divided, according to a proposal of the invention, into an outside stator part that forms an air gap with the rotor, and an inside stator part that forms a control air gap with the outside stator part that surrounds it, it is possible, in simple manner, to control the magnetic flow in the stator by rotating the inside stator part, thereby changing the geometry of the control air gap. By means of such a change of the control air gap as a function of the angle of rotation of the inside stator part, it is possible to achieve a monotonous progression of the magnetic flow, which is proportional to the induced voltage, while adhering to low voltage tolerances.
According to the invention, rotation of the inside stator part takes place in accordance with the load-dependent variations of the terminal voltage of the generator, where the magnetic resistance in the stator decreases as the control air gap becomes increasingly smaller, i.e. vice versa, increases as the control air gap becomes increasingly larger.
For this purpose, the circumference surfaces of the two stator parts that are adjacent to the control air gap can have a plurality of segment-like projections, viewed over the circumference, preferably in such a way that each stator part has at least three segment projections, the contours of which deviate from the circular shape in the opposite direction. This means that with reference to one direction of rotation, the segment projections of the inside stator part increasingly come closer to those of the outside stator part, while in the opposite direction of rotation, they increasingly move apart from one another, increasing the size of the control air gap.
In accordance with another proposal according to the invention, it is provided that the outside stator part is arranged fixed in place on the housing, where it is practical if it is attached to a lid part of the generator housing, and that the inside stator part is held inside it, centered and so as to rotate.
This is advantageously done in that the inside stator part is mounted to rotate with a hollow shaft, which is mounted to rotate in bearing flanges on both sides of the inside stator part, which are connected with the outside stator part, e.g. in such a manner that the bearing flanges are formed on lateral sheathing plates, which are screwed onto the outside stator part.
In structuring the rotation of the inside stator part in accordance with the load-dependent variations of the terminal voltage of the generator, it is provided, according to the invention, that a rotary magnet is mounted on an extension of the hollow shaft on the housing lid side, so as to rotate with it, and that its rotation within an assigned iron yoke attached to the housing is controlled by the yoke winding, which is connected to the generator terminal voltage. In this way, a voltage regulation that is independent of the power factor cos xcfx86 is achieved.
A particularly advantageous structure of the invention results from the aforementioned arrangement of the inside stator part on a hollow shaft. Almost force-free rotation of the inside stator part by means of the rotary magnet can be achieved by the fact that a torsion rod that is connected with the hollow shaft and acts between the stator and the rotary magnet is designed in such a way that the torsion force corresponds approximately to the magnetic force exercised on the inside stator part by the magnetic field, independent of the angle of rotation. With this adaptation, the geometry of the control air gap, which depends on the angle of rotation, is very important. Practically force-free voltage regulation can be achieved by a corresponding adaptation to the spring force of the torsion rod in the hollow shaft.